Method and apparatus for making drill bits



Oct. 17, 1950 P. LIDDICOAT llE'l'l-IQD AND APPARATUS FOR MAKING DRILLBITS Filed Dec. 4, 1947 2 Sheets-Sheet 1 z %2'E'z -1 ZE::.- PERC/LLLIDDICOAT.

P. LIDDICOAT METHOD mm APPARATUS FOR MAKING mum. BITS Oct. 17, 1950 2Sheets-Sheet 2 Filed Dec. 4, 1947 PER CILL LIDDICOAT.

Patented Oct. 17, 1950 I S PATENT OFFICE METHOD AND APPARATUS FOR MAKINGI DRILL BITS Percill Liddicoat, Niagara on the Lake,

' Ontario, Canada Application December 4, 1947, Serial N0. 789,633

13 Claims. 1'

This invention relates to the manufacture of articles such as drill bitsand the like and includes an automatically-operating wedge die forshaping the articles.

Specifically this invention deals with the dieforging of drill bits orthe like in a split die so arranged relative to a die holder that thedie segments are wedged together during the forging step, automaticallyseparate as the forged article is retracted, and then automaticallyreturn to closed position to form a support for the retracted article.

While the invention will hereinafter be specifically described inconnection with the manufacture of drill bits, it should be understoodthat the invention includes the die-forging of other shapes andespecially shapes which necessitate separation of die segments to permittheir release from the die cavity.

In accordance with this invention a pair of opposed dies, having 'flatmatingfaces at the parting line therebetween, are provided with taperedend walls for wedging engagement in a die block to hold the mating facesin wedgedtogether relationship for maintaining a true die cavity. Thedie block is sufiici'ently strong and rigid so that it will not deformeven when subjected to tremendous expanding pressures such as mightoccur during a forging operation tending to. separate the dies. The dieshave the forming cavity therein communicating with the top walls of thedies through a reduced punchreceiving passage.

A punch of a, die press is reciprocally mounted through a stripper barand has an active lower end fitting into the punch passage to act on abillet inthe ,die cavity for forging the billet into the shape of thecavity. The punch also pierces and enters into the metal of the billetto form a recess therein and to become firmly connected.

with the finished article. Retraction of the punch causes the article toraisewith the punch.

Since the die cavity'is wider than the punch passage, and since thearticle fills the die cavity, the article cannot be removed from thecavity unless the dies are opened up.

The retracting movement of the punch and article tends to raise the diesfrom the die block, and, since the dies are top-heavy, they tend to rideon their tapered end walls until they are lifted out of the die block asuflicient distance so that they can tilt on these end walls to an openposition. The die block can be equipped with means to aid or initiatethis tilting of the dies. The tilted dies open up a path sufiicientlylarge for removal of the article from the die cavity. Upon removal ofthe article, the dies fall by gravity back into the die block whichguides them to again place their mating faces in mated engagement forthe next die-pressing operation. j

As the punch is retracted through the stripper bar, the article impaledon the punch is stripped from the end of the punch and falls by gravityon top of the closed dies. Since the article is wider than the punchpassageway or die hole in the top of the dies, the stripped article willrest on top of the dies where it can be easily removed.

In one embodiment of the invention thedies have mating semi-circularrecesse in their side Walls receiving a circular disk. These disksfunction as turning axes or pivots for the dies and prevent misalignmentof the dies in the block.

In another embodiment of the invention the dies have cam grooves intheir side walls receiving pins carried by the die block to guide thedies between closed abutted-together position and open tilted-apartposition.

; It is, then, an object of this invention to provide a method andapparatus for forming shaped articles in a die cavity in such a mannerthat the die cavity will always be maintained in proper closed conditionduring the forming operation and will automatically open up to permitdischarge of the shaped article.

'A further object of the invention is to provide a split die arrangementfor die-forging operations wherein separate die segments are wedgedtogether during a die-pressing operation and are automatically separatedto open up the die cavity whenever an article shaped therein isretracted out of the dies.

A further object of the invention is to provide a die-forging apparatusespecially suitable for making drill bits or the like vrhereincomplementary die segments are wedged into closed position during theforging operation and are automatically separated to open up the diecavity whenever the forged article is retracted from the die cavity.

A stillxfurther object of the invention is to provide a method of makingshaped articles such as drill bits or the like by pressing a plungeragainst a metal billet in a die cavity for simultaneously shaping thebillet to the contour of the cavity and impaling the shaped article onthe plunger.

A still further object of the invention is to provide a method of makingshaped articles with hollow shanks by simultaneously impaling thearticle on a, punch to form the hollow shank and deforming the body ofthe article to the desired shape in a die cavity.

Another object of the invention is to provide a method of makingrecessed shaped articles wherein a plunger acting on a billet in the diecavity of a split die simultaneously pierces the billet to form therecess anclpresses the billet into conformity with the die cavity toimpale the shaped articles thereon whereupon retraction of the plungerwill carry the article therewith and separate the split dies, to open upa discharge path for the article.

A still further object of the invention is to provide a method of makingshaped articles in a-die-forging press wherein the article is shaped inthe die cavity of a split die by a plunger which pierces the article andretracts the shaped article from the split die to carry it above the dieand wherein further retractive movement of the plunger results instripping of the article therefrom to fall by gravity on top of theclosed die.

Another object of the invention is to provide die-forging apparatusincluding die segments held by a die block in wedged-togetherrelationship during the die-pressing operation, and arranged toautomatically separate upon retraction of the shaped article therefrom.

Another object of the invention is to provide dieforging apparatuswherein split dies coact v to define an entrance hole and an enlargeddie cavity and wherein a die punch impales an article being forged inthe die cavity for retraction through the entrance hole as the diesautomatically tilt to open up the entrance hole.

A still further object of the invention is to provide a splitdie-forging apparatus including means for automatically maintaining thedies in alignment and guide means for directing the dies between closedand opened positions.

Other and further objects of the invention will be apparent to thoseskilled in the art from the following detailed description of theannexed sheets .of drawings which, by way of preferred examples only,illustrate two embodiments of the invention.

On the drawings:

Figure 1 is a top plan view of one form of dieforging apparatusaccording to this invention.

Figure 2 is a vertical cross-sectional view, with parts in endelevation, taken along the line II- of Figure 1.

Figure 3 is a vertical cross section, with parts in side elevation,taken along the line IIIIII of Figure 1 and also showing the die-forgingpunch and a billet or work piece in the dies.

Figure 4 is a view similar to Figure 3 but showing the position of thepunch at the end of the forging stroke and illustrating the manner inwhich the billet or work piece is pierced and shaped.

Figure 5 is a view similar to Figure 4 but illustrating the positions ofthe parts when the punch is retracted to remove the shaped article fromthe die cavity.

Figure 6 is a view similar to Figure 4 but illustrating the positions ofthe parts as the finished article is stripped from the punch, andshowing, in dotted lines, how the finished article rests on top of thedies after the stripping operation.

Figure '7 is a vertical cross-sectional view, with parts in sideelevation, taken along the line VIIVII of Figure l and showing, indotted lines, the manner in which the disk serves to maintain the diesin alignment.

Figure 8 is a vertical cross-sectional view, with parts in sideelevation, showing a plunger and shaped articles in another arrangementof dies according to this invention.

Figure 9 is a view similar to Figure 8 and illustrating the manner inwhich cam grooves and guide pins direct the dies between open and closedpositions.

Figure 10 is a fragmentary cross-sectional view taken along the line X-Xof Figure 9.

As shown on the drawings:

In the embodiment ll] of the invention shown in Figures 1 to 7inclusive, a heavy rigid die block II has an open-topped close-bottomedrecess receiving a pair of dies I2, l2. A separator I3 is mounted on topof the die block I l. to spread the dies I2, I2 apart during thedischarge step of the process. Circular metal disks l4, I4 are providedfor maintaining the dies l2, I2 in alignment. A punch I5 is slidablymounted through a stripper bar I 5 and is effective to force a billet Binto conformity with the die cavity of the dies l2, I2 while piercing anend face of the billet B.

The recess of the die block II has tapered end walls Ila, Ila andvertical side walls llb, llb together with a flat horizontal bottom llc.The end walls Ila, Ila diverge from the bottom wall llc at a wedgingangle. Each wall Ila preferably diverges at least 8 from the vertical.The taper is continuous from the top to the bottom of the recess.

The dies I2, l2 have tapered end walls I211, I201 mating with the endwalls Ila, Ila and have vertical side walls I2b, l2b mating with theside walls llb of the die block. The dies also have flat horizontalbottom walls I2c lying in spaced relation above the bottom wall llc ofthe die block. These bottom walls In extend inwardly from the taperedend walls I2a to rounded surfaces I2d which curve inwardly and upwardlyto flat mating walls He. The mating walls I2e, I 2c are abutted firmlytogether b the wedge relationship of the end walls I l a and I2a. Itwill therefore be noted that the parting line between the dies l2, I2 isbetween the tapered walls of the die block and the taper of the dieblock is toward this parting line for maintaining a wedged-togetherabutting condition of the dies when the same are urged toward the bottomof the recess in the die block. The dies will be abutted together by thewedging walls before they are bottomed on the wall llc of the die blockso that this wall will not resist the wedging action.

Each die l2, l2 has a semi-recess in its mating face l2e thereof. Thesesemi-recesses of the dies coact to define a cylindrical entrance hole orpassageway I1 and a shaping cavity Is. The entrance hole or passage l1extends downwardly from the top wall of the dies to the top of theshaping cavity l8 and has a diameter sized for snugly receiving thepunch I5. The shaping cavity I8 is wider than the passage l1 and a topshoulder i9 is provided Y of the die cavity [8. The punch It acts onthis billet B as shown in Figure 4 to form the drill bit DB conformingwith the shape of the cavity It. At the same time, however, the leadingend of the punch i pierces the top end of the billet to form a shankrecess 20 in the drill bit DB. The drill bit DB becomes impaled on theleading end of the punch. a 7

During the downward stroke of the punch, the mating faces He, He of thedies are continually forced toward each other by the tapered end wallsof .the die block so that'the die cavities are continuous and theparting line between the dies is tightly closed to eliminate flashing ofbillet metal between the dies.

The side walls of the dies l2, l2 each have semi-circular recesses i2!therein near the bottoms of the dies. These recesses extendsymmetrically on opposite sides of the parting line between the dies andhave their centers on the parting line. The disks l4 fit in the recessesI21. one-half of each disk being seated in the semirecess of each die.The disks are effective to hold the dies in alignment and also functionas tuming axes for tilting of the dies during the discharge operation. Q

After the punch has reached the end of its forging stroke, it isretracted upwardly and carries the drill bit DB therewith. Thisretractive movement of the drill bit raises the dies relative to the dieblock since the top of the drill bit will act against the shoulder I! ofthe die cavity. Raising of the dies relative to the die block, ofcourse, ..moves the dies to the enlarged upper portion of the die blockrecess and, since the dies are top-heavy, being thicker at the top, thesame will ride on and tilt about the tapered walls of the die block asbest shown in Figure 5. As the dies tilt on the tapered walls iia of thedie block, the die cavity is opened up so that the drill DB is readilyremoved from the dies as illustrated in Figure 5.

In order to initiate separation and tilting of the die blocks during theretraction of the punch and drill bit, the separator device I3 isprovided on the die block Ii. This device it has a finger l3a' overlyingthe parting line between the dies l2, l2. The finger, as shown in Figure3, is of triangular cross section with a pointed end arranged to enterthe parting line so that, as the dies are raised, the diverging sidesthereof will separate the dies. This device I3 prevents any possibleadherence of the dies during the retraction step, so that the diescannot be simultaneously lifted straight up out of the die block recesswithout riding o the walls ila. of the recess. The device l3 can beaiiixed to the top of a side wall of the die block as shown in Figure 1.

As shown in Figure 6, when the punch I5 raises the drill bit DB up tothe stripper bar It, this bar stops further upward movement of the bitand the punch is retracted through the bar and out of the bit. In themeantime the dies, upon being freed of the drill bit, fall by gravityback into the recess of the die block II and automatically come togetherfor the next forging operation. Since the drill bit is larger than theentrance hole or passageway ll of the closed dies i2, i2, it will reston top of the dies after it is stripped oil! of the punch. In theforging machineequipped with the dies, punch, and stripper bar thefeature of supporting the stripped-off drill bits on the closed diesproduces a convenient arrangement since the stripped-off bits can thenbe automatically removed by a blast of air, by a discharge arm, or anyother suitable mechanism.

In the modified embodiment Illa of the invention shown in Figures 8 to10, parts identical with parts described in Figures 1 to 7 have beenmarked with the same reference numerals. As shown in Figures 8 and 9,the disks ll of the embodiment shown in Figures 1 to 6 are eliminatedand the die blocks I2, I 2 are guided between open and closed positionsby means of pins 2| projecting from the side walls of the die block intogrooves 22 in the side faces l2b of the dies. These grooves 22 form camtracks to guide the dies from the abutted-together closed position shownin solid lines in Figure 9 to the separated open position shown indotted lines in Figure 9. The pins are positioned near the upper ends ofthe die block i I as shown in Figure 9.

The rounded surfaces 12d of the dies l2, as best shown in dotted linesin Figures 7 and 9, ccact to provide turning fulcrums for the dies asthey are tilted back on the tapered walls Ila of the die block and makepossible a greater angle of tilt for the dies. Thus the cutaway roundedcorners permit the dies to tilt apart along a rounded fulcrum and, ofcourse, the disks ill or the pins 2i hold the dies in alignedrelationship so that one die cannot become offset relative to theothers.

The arrangement of Figures 8 to 10 operates identically as described inconnection with Figures l to 7.

From the above descriptions it should be evident that the inventionprovides a method and apparatus for shaping articles in a die cavity andfor removing the shaped articles from the cavity by automaticallyseparating die segments during the removal step.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention and it is, therefore, not the purpose to limit thepatent granted hereo otherwise than necessitated by the scope of theappended claims.

I claim as my-invention:

l. The method of shaping articles'in'a die cavity defined by a pluralityof die segments which comprises placing a billet in the die cavity,pressing a punch against an end of the billet, simultaneously piercingthe billet with the punch and shaping the billet into conformity withthe die cavity to impale a shaped article on the punch,

retracting the punch and article impaled thereon, separating the diesegments during said retracting step to open up a discharge path for thearticle, guiding the die segments back to closed position, stripping thearticle from the punch, and depositing the stripped article on top ofthe die segments,

2. The method of forging an article in a multisegment die whichcomprises wedging the die segments toward each other, inserting a billetinto the cavity defined by the wedged together segments, forcing a.punch into said cavity against the end of said billet to simultaneouslypierce and shape the billet into conformity with the die cavity toproduce a shaped article impaled on the punch, retracting the punch withthe article impaled thereon, separating the die segments during saidretracting step to open up the die cavitythereof and provide a,discharge path for.

the article, guiding the article-freed die segments back intowedged-together relation, stripping the article from the punch, anddepositing the stripped article on the die segments. v

3. The method of making articles with hollow shanks in a multi-segmentdie which comprises seating the die segments in a die block havingconverging walls, pressing the segments toward ments back into the dieblock into wedged-to gether relationship, stripping the article from thepunch, and depositing the stripped article on top of the wedged-togethersegments. l

4. Die forging apparatus comprising a die block, a plurality of diesegments in said die block. said die block having tapered walls arrangedto wedge together said die segments, a spreader member on said die blockoverlying the parting line between said die segments to separate thesegments as ,they are raised out of the die block, fulcrum means forsaid dies forming a tilting axis for the spreading dies, a punch havinga leading and adapted to enter said dies, and a stripper bar receivingsaid punch therethrough for removing an article impaled on the punch.

5. Die forging apparatus comprising a, die block having an open-toppedclosed-bottomed recess with tapered end walls converging toward thebottom of the recess, a pair of die segments having fiat mating endfaces with fragmental die cavities therein and having tapered opposedend gauges 1 recess, said die segments coacting to define a shaping diecavity and an entrance hole thereto, aspreader device on said die blockoverlying the parting line between said die segments to separate thesegments and open up the die cavity as the segments are raised out ofthe die block, and means carried by the die segments for holding ,thesegments in aligned relationship to prevent one segment from beingoflset relative to the other as the segments are raised from and loweredinto the recess of the die block.

8. Die forging apparatus comprising a die block having a cavity/ withconverging end walls, a pair of die segments seatable in said cavity andhaving tapered end walls cooperating with said con- "verging end wallsto wedge the segments together as-the same are forced into the cavity,pin means projecting into said cavityyand cam grooves in said diesegments for receiving said pins to guide the segments between aspreadapart open position and a closed wedged-together position.

9. Drill bit forging apparatus comprising a die block having anopen-topped recess with converging end wa1ls,' a pair of die segmentsseatable in said recess and arranged to be wedged ,together when forcedinto the recess, a punch faces coacting with the tapered end walls ofthe die block recess to wedge the mating faces of the die segmentstogether, apunch adapted to enter the die cavity of the wedged-togetherdie segments for acting on a work piece therein and having a leading endarranged to pierce the work piece to impale the article shaped therefromon the punch, a stripper bar slidably receiving the punch therethrough,and fulcrum means for guiding the die segments against said tapered endwalls of the die block as the shaped article is retracted from the diecavity for separating the die segments to open up the die cavity.

6. Die forging apparatus comprising a die block having a cavity withopposed tapered walls. a pair of die segments seated in said cavityhaving tapered walls coacting with the walls of the cavity for urgingthe segments together, said segments coacting to define a shaping cavityand an entrance hole, means on the die block overlying the parting linebetween the dies to separate the dies as the same are raised out of thedie block, said dies having semi-circular recesses in the side faceshaving a leadingend arranged to enter the die cavity of the die :blocks,said punch receiving a work piece thereon to carry the work piecetherewith, a stripper bar slidably receiving the punch therethrough, andguide means for separating the die segmentsas the work piece is raisedout of the die block, said die block guiding aid segments back intoclosed pcsition after said work piece is removedtherefrom, and saidstripper member arranged to'separate the work piece from the punch fordeposit on the closed die segments.

10. The method of die forging drill bits or the like which comprisesproviding a pair of mating dies with complementary, die cavities in themating faces thereof, seating said dies in a die block having taperedwalls opposite the mating faces of the dies for wedge action on the diesto hold the mating faces in abutted together relation, pressing aplunger into engaging relation with a work piece in said die cavity toconnect the plunger and work piece and to shape the work piece intoconformity with the cavity, re-

tracting the plunger from the dies to raise the thereof with centers onthe parting line between shaped article therewith and cause the articleto simultaneously raise the dies relative to the die block, andspreading the dies as they rise to thereby open up the die cavity fordischarge of the shaped article.

11. The method of making shaped articles which comprises urging themating faces of a pluralityof dies together to form a die cavity with arestricted entrance hole partially defined by each die, pressing a workpiece in the die cavity of said dies to spread the work piece laterallyof said hole into conformity with said die cavity and form a shapedarticle wider than said I hole, forcing the shaped article toward saidhole,

and utilizing said force to effect separation of the mating faces of thedies to open up said hole for forming a discharge path from the diecavity accommodating discharge of the shaped article.

12. A die construction comprising a strong rigid die block having arecess with vertical side walls and end walls converging from the top ofthe block at a minimum angle of about 8 from the vertical, a pair of diesegments fitting in the recess in said block and having vertical sidewalls and tapered end walls coacting respectively with the vertical sidewalls and converging end walls of the recess, said die segments havingmating end faces with segmental die cavities therein arranged to coactin forming a closed die cavity when the mating faces are abuttedtogether, each die segment having a semi-circular recess in eachvertical side wall thereof and the semicircular recesses in adjacentside walls mating to form a circular recess when the diesare closed, acircular disk in each of said mated circular recesses forming a tiltingaxis for the dies while holding the dies in aligned relationship, andsaid dies having rounded surfaces joining their mating faces with thebottom ends thereof to facilitate tilting of the dies about the circulardisks.

13. Die forging apparatus comprising a die block, die segments seatablein said block, said segments having complementary semi-recesses in thesides thereof near the bottoms thereof and communicating with theparting line between the segments, and a disk in said recess adapted tohold the die segments in alignment in said block while forming a fulcrumaccommodating tilting of the segments thereabout as the segments aremoved out of the die block.

PERCILL LIDDICOAT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 116,012 Beecher June 20, 1871240,174 Pearce Apr. 12, 1881 1,261,084 Wilcox Apr. 2, 1918 1,328,276Fuchs Jan. 20, 1920 1,377,094 Root May 3, 1921 1,958,705 Klein May 15,1934 2,066,360 Nast Jan. 5, 1937 2,134,386 Wolf Oct. 25, 1938 2,340,529Hartman Feb. 1, 1944 2,371,041 Flowers Mar. 6, 1945 2,398,244 MortensenApr. 9, 194

